Geiger Muller counters are gas-filled instruments that detect and measure ionizing radiation such as alpha, beta, and gamma rays. They work by ionizing gas within a tube, producing electrons that create an avalanche effect and pulse that can be amplified and counted. The sensitive region of operation is the plateau region where the count rate remains constant over a range of applied voltages. While GM counters are widely used due to their high sensitivity, they have limitations such as an inability to measure energy and detect uncharged particles like gamma rays.

1. S.S. Jain Subodh P.G. (Autonomous) College
Affiliated to Rajasthan University

2. Geiger Muller
Counter
Presented by
ASHOK KUMAR
GURJAR
Roll no.- 2285013

3. CONTENT
• Introduction
• History
• Principle
• Working
• Characteristics of G.M. Counter
• Graph
• Conclusion
• Advantages
• Disadvantages

4. INTRODUCTION
Geiger Muller Counter is a gas filled instrument
which is used for detecting and measuring
ionizing radiation such as alpha, beta and
gamma radiation.

5. HISTORY
In 1908 The first model of G.M. Counter was
developed by HANS GEIGER and ERNEST
RUTHERFORD which was only capable of detecting
ALPHA particle and after were able to BETA particle

6. PRINCIPLE
The ionizing particle passing through the tube ionizes
the gas and electrons so produced move towards
Anode. The velocity is quite high and they later
produce secondary electrons after repeated collisions
with the particles of the gas.

7. WORKING
The tube is filled with Argon gas, and around voltage of +400 Volts
is applied to the thin wire in the middle. When a particle arrives
into the tube, it takes an electron from Argon atom. The electron is
attracted to the central wire and as it rushes towards the wire, the
electron will knock other electrons from Argon atoms, causing an
"avalanche". Thus one single incoming particle will cause many
electrons to arrive at the wire, creating a pulse which can be
amplified and counted. This gives us a very sensitive detector.

8. WORKING

9. CHARACTERISTICS OF GM
COUNTER
• If the applied voltage is increased further, then a point will be reached
after which the count rate remains constant over a certain region. This
region is known as plateau region or Geiger region. This region is
used for Geiger Muller operation.
• Beyond the plateau region the applied electric field is so high that a
continuous discharge takes place in the tube and the count rate
increases very rapidly. It does not require any ionization event to
happen so that the tube must not be used in this region.

10. GRAPH

11. • DEAD TIME –
The time during discharge which remain insensitive
is called DEAD TIME.
• RECOVERY TIME-
The time for which counter takes its original count rate ,
known as RECOVERY TIME.
• PARALYSIS TIME –
The means of recovery time and dead time is known as
PARALYSIS TIME.

12. EFFICIENCY
E = NO. OF PARTICLES OF RADIATION DETECTED
NO. OF PARTICLES OF RADIATION EMITTED

13. CONCLUSION
• Geiger Moller Counter are regarded as one of the
best radiation detection instrument and is used
widely and prominently.
• Geiger Moller Counter are used in numerous fields
and it is regarded as best tool for detection and
measurement if ionizing radiation.

14. ADVANTAGES
• G.M. Counter can count alpha particle , beta
particles and cosmic as well.
• They have high sensitivity.

15. DISADVANTAGES
• Energy can not be measured by it as it has a lack of
differencing abilities.
• It can not detect uncharged particle like Gamma
particle.
• It is less efficient due to the large paralysis time
limits and large dead time .